tag:blogger.com,1999:blog-7785493.post1590095130351408569..comments2015-08-02T23:49:53.783+03:00Comments on Dienekes’ Anthropology Blog: X chromosome diversity in Africans and non-AfricansDienekeshttp://www.blogger.com/profile/02082684850093948970noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-7785493.post-20289376409448721022008-12-23T22:23:00.000+02:002008-12-23T22:23:00.000+02:00John: abslutely yes. Though you don't really need ...John: abslutely yes. Though you don't really need to look for bottlenecks that are not such thing (even the black death did not cause enough casualties as to be considered a bottleneck, properly speaking). Mere drift will cause some clades to vanish and others to expand randomly all the time. Smaller clades are, of course, more likely to succumb in the process. <BR/><BR/>But there may be other reasons: if some mtDNA clades, for example, carry a deletereous mutation (as does happen), they won't surely survive for too many generations. In fact all deletereous mutations found in extant mtDNA are at the very end of the tree, in newly sprung branches that are not likely to survive in the mid run. Inversely, though the examples are less clear, there could be some clades that give some marked advantage (greater fertility, improved constitution...) and these would be more likely to get consolidated in the mid-run - <I>ceteris paribus</I>.Majuhttp://www.blogger.com/profile/12369840391933337204noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-48379568417434760562008-12-23T19:31:00.000+02:002008-12-23T19:31:00.000+02:00Hello. This raises for me a question much on my mi...Hello. This raises for me a question much on my mind as I look to sort out what all these articles mean. The question is, to what degree are mini extinction events taken into account in calculating relative diversity. Example: Otzi was reported to be of a different configuration of mtDNA than has yet been found in the region. I look at the 10,000 or so bodies in the mass grave in the Greek region of Sicily and wonder if those COULD be typed, would there be groups among them no longer among us. Especially considering the Black Death, WWI, WWII and the impact of the Ice Age on those groups living in Europe at the time, I think this has to be a much larger factor in the equation than I have yet seen reflected in articles. But that maybe is the measure of MY ignorance.Johnhttp://www.blogger.com/profile/02822120230321781593noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-23068069159353758522008-12-23T17:53:00.000+02:002008-12-23T17:53:00.000+02:00I wonder if in extremely violent or war-like cultu...I wonder if in extremely violent or war-like cultures, you wouldn't get genetic data that looked like the footprint of polyandry simply because so many men die before being able to father multiple children by the same woman.Kosmohttp://www.blogger.com/profile/05156165962330239126noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-68380391104170773412008-12-23T03:20:00.000+02:002008-12-23T03:20:00.000+02:00Self-reply to the last paragraph: surely the paper...Self-reply to the last paragraph: surely the paper was already submitted before the other paper was published. The contradiction remains though.Majuhttp://www.blogger.com/profile/12369840391933337204noreply@blogger.comtag:blogger.com,1999:blog-7785493.post-67793755682443966812008-12-23T03:17:00.000+02:002008-12-23T03:17:00.000+02:00Earlier reference in your blog re. this issue:Poly...Earlier reference in your blog re. this issue:<BR/><BR/><A>Polygyny in human evolution</A>, just three months ago.<BR/><BR/>In that other paper none of the ratios was under the 0.75 line but actually all were well above, and more in Eurasians than among Africans. <BR/><BR/>My own derived figures were:<BR/><BR/>- San (Bushmen): 0.85 (13% over neutral expectation)<BR/>- Biaka Pygmies: 0.90 (20% excess)<BR/>- Mandenka (West Africans): 0.93 (24% excess)<BR/>- Han Chinese: 0.94 (25% excess)<BR/>- Melanesians: 1.04 (39% excess)<BR/>- Northern Basques: 1.05 (40% excess)<BR/><BR/>The norm was here clearly higher than 0.90 (only San were under this) and the authors then suggested widespread poligyny<BR/><BR/>Now this paper is saying exactly the opposite. Hmmm...<BR/><BR/>So what now? Eurasian Polyandry? Let me be skeptic, specially when the data is so contradictory. <BR/><BR/>I find also strange that this study does not even mention the previous one and this striking contradiction, at least in the abstract.Majuhttp://www.blogger.com/profile/12369840391933337204noreply@blogger.com